Memory cells of electronic memory devices such as dynamic random access memory typically employ a number of electronic components in order to save data. For instance, in order to store data, a combination of electronic components such as transistors, diodes, and/or capacitors are typically employed in such memory cells to store or not store electrical charges. If a charge is stored in such a memory cell, that may indicate a logic “1,” and if no charge is stored in such a memory cell that may indicate a logic “0.”
An alternative approach for storing data is to use memory cells made of phase change material. A phase change material is a material that can be placed into at least two physical states, a crystalline state and an amorphous state, by increasing or decreasing temperature. By changing the physical state of the phase change material, certain characteristics of the material, such as electrical resistance, may also change. Such properties may be exploited in order to form memory cells made of phase change material.
Such memory cells, particularly in high densities, are generally intricate and expensive to manufacture. One method for forming high-density arrays includes a two-step patterning of round holes for forming the phase change memory elements, each pattern being within the resolution of the capability of the photolithographic process. Even if a desired degree of density is achieved, however, filling the holes void-free is difficult. This is increasingly true due at least in part to increasing aspect ratios resulting in poor step coverage.